Dirt Bike Tech Tip: How To Replace Motocross Steering Head Bearings
If you are a motocross enthusiast, most likely you have had to replace the steering head bearings on your dirt bike at some point. You’ll know when it’s time to replace them, when your handle bars will not turn from side to side as smoothly as they used to. Instead, the steering from side to side feels very ‘notchy’. That ‘notchy’ motion is caused by the bearings not moving smoothly around the steering stem or inside the bearing’s collar (the housing that your bearing sits in). Intense ‘grinding’ of the bearing back and forth, inside it’s housing, eventually causes steering hesitation on your bike. This can be dangerous if not addressed, and we recommend changing your head bearings as soon as you notice the notchy friction. Always consult a professionally trained mechanic if you are unsure of your ability to complete the job yourself. You certainly want smooth steering when shredding your favorite berms, and you don’t want to risk the head bearing freezing on you while trying to steer. Dirt and water are the main reason head bearings eventually need replacement. Dirty water can seep into the head bearing housing and into the balls of the bearings, causing the head bearings to have increased friction and slowly build up grooves and notches when moving back and forth over time. Excessive pressure cleaning or riding in extremely dirty and muddy conditions, can increase the likelihood of contaminating the bearings. This contamination of dirt and water accelerates wear on the head bearings and their collars.
As a rule of thumb, we usually use OEM replacement head bearings. However, many aftermarket companies, such as Pivot Works or All Balls Racing also manufacture and sell replacement head bearing sets. We have had excellent results with All Balls Racing bearings. All Balls Racing bearings are well made, and are used by many professional motocross mechanics for superior strength and quality. We have never tried Pivot Works bearings but have also heard good feedback about them too.
Replacing head bearings is a fairly easy task. The video above, created by the folks at Pivot Works, should help you with the task. There are two head bearings, an ‘upper head bearing’ and a ‘lower head bearing’. Most of the time these two bearings are the same size and come in a kit. Both bearings rotate along the dirt bike’s steering column, and sit within the bearings housing or collar. The most difficult aspect of replacing the steering bearings yourself, is removing the lower head bearing. Everyone seems to have their own technique. Some mechanics carefully grind the lower bearing off of the stem, while others choose to ‘cut’ the bearing off. Other’s claim it is simple to just carefully ‘tap’ the lower head bearing off of the steering stem by using a hammer and a punch. A punch is also used to remove the bearing collars that sit within the dirt bikes frame. It is important to use lots of high quality grease, and pack the new bearings properly. Properly greased bearings will extend the bearing’s life and help keep mud and water out. The other tricky part when replacing head bearings is knowing how to correctly ‘press’ the new lower head bearing onto the steering stem. Many riders choose to simply remove the steering stem themselves, and have a professional mechanic ‘press’ the new bearing onto the steering stem by using a professional press machine. A special tool can also be used to install the new collars into the dirt bike frame.
Be careful never to spray water directly into the steering bearing area when pressure cleaning your bike, and always replace head bearings immediately upon first notice of notchy steering. Cheers, Chronic MX.